Insulation material and method for manufacturing the insulation

ABSTRACT

The invention relates to a coating for insulation material, which coating comprises a metal layer, such as an aluminum layer, and a plastic layer. The plastic layer contains plastic that crystallizes when heated. The plastic can more particularly be a polyamide.

This application is a division of prior application No. 10/081,133,filed on Feb. 22, 2002, which is a continuation of InternationalApplication No. PCT/FI00/00716, filed Aug. 24, 2000 and designating theUnited States of America, which are hereby incorporated herein byreference in their entirety.

FIELD

The invention relates to building materials and applies to a coating foran insulation material. The coating includes metal, such as aluminum.The invention also relates to the manufacture of the coating, and itsuse in insulation materials. The invention is suitable for use, forexample, in insulation materials containing cellular plastics or fibrewool.

BACKGROUND

Various insulation materials, in which a coating has been joined to aporous insulation layer, are applied in construction technology. Thecoating can be used to improve the insulating properties, durability,fire safety, dimensional stability, or the appearance of the material.

Aluminum foil is often used in the coatings of insulation materials. Itis impermeable to gases and is incombustible, and reflects thermalradiation. The aluminum foil is joined to the insulation layer by meansof a plastic adhesion layer. The insulation material is manufactured inthe following manner: firstly, the adhesion layer is joined to thealuminum sheet, after which the laminate that has thus been produced isjoined to the insulation layer. This can be done, for example, withpolyurethane while it is still in a reactive state, whereby the layersself-adhere without separate gluing. When there is a gas-tight aluminumlayer against the layer of cellular plastic, the propellants in thecellular plastic remain inside it to an optimal degree.

One problem here is, however, the insufficient strength of the coatingduring the manufacture of the insulation material. The aluminum sheet iseasily torn when it is pulled into the machine. For example, during thecoating of a polyurethane insulation that is still forming, failures areparticularly harmful, as the expanding polyurethane foam is spread andstains the production machinery and floor. In fact, the primary functionof the coating in such a situation is to protect the process machineryfrom reactive and sticky insulation material in the initial phase of theprocess.

SUMMARY

The present invention relates to a coating for an insulation materialcomprising a metal layer, such as an aluminum layer, and a plasticlayer. The plastic layer contains a plastic that crystallizes whenheated. The plastic layer is adhered to the metal layer. The plastic issuch that it can be joined to the metal film particularly by extrusion.The plastic may be a polyamide, such as polyamide-6 or polyamide-66. Thetemperature at which the plastic crystallizes may be, for example, 100to 160° C. An adhesion layer can also be provided between the metallayer and the plastic layer.

The invention also relates to a method for producing an insulationmaterial coating in which a metal layer, such as for example, analuminum layer, is joined by extrusion to a plastic layer containingextrudable plastic that crystallizes when heated.

The invention also relates to a manufacturing method for an insulationmaterial in which a coating is joined to an insulation layer such asexpended plastic or fiber wool. The coating contains a metal layer, suchas for example an aluminum layer, and a plastic layer. In the method,the coating is joined to an insulation layer, and the plastic layercomprises plastic that crystallizes when heated. The plastic layer isheated so that the plastic crystallizes. In particular, the insulationlayer may consist of expanded or cellular plastic, such as polyurethaneor polystyrene. The coating can thus be attached to the insulation layerwhile the insulation layer is being formed. When the forming of theinsulation layer is exothermic, the heat that is generated can beutilized in crystallizing the plastic of the plastic layer.

During the process of manufacturing the insulation material, the plasticlayer protects the coating, especially from tearing. Whilecrystallizing, the plastic layer becomes rigid, and thus the insulationmaterial gains solidity and surface strength.

The invention also relates to an insulation material with an insulationlayer having a coating joined to it where the coating includes a metallayer, such as for example an aluminum layer, and a plastic layer whichcontains a polyamide that crystallizes when heated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an embodiment of the invention having anexpanded polymer;

FIG. 2 is a side view of an alternate embodiment of the invention;

FIG. 3 is a side view of an alternate embodiment of the invention havinga fibrous material; and

FIG. 4 is a side view of an alternate embodiment of the invention.

DETAILED DESCRIPTION

In the embodiment shown in FIG. 1, a layer 2 (e.g. about 30 g/m²),containing a polyamide-6 that crystallizes when heated, has first beenattached to an aluminum layer 1 (e.g. about 50 μm). The coating thusobtained has been joined to the foamed polyurethane layer 3 in such away that the polyamide layer remains therebetween, and the polyamidelayer 2 has been heated in order to crystallize the polyamide.

In order to improve the adhesion between the aluminum layer 1 and thepolyamide layer 2, an adhesion layer 4 containing a suitable adhesiveplastic is provided between them. Correspondingly, to improve theadhesion between the polyamide layer 2 and the polyurethane layer 3, anadhesion layer 5 is provided between them. Furthermore, the outersurface of the aluminum layer 1 is coated with a surface layer 6 (e.g.HD-polyethylene). The surface layer 6 may contain necessary additives,particularly a fire retardant.

A product according to FIG. 1 can be manufactured particularly by firstattaching an adhesion layer 4, a polyamide layer 2, an adhesion layer 5,and a surface layer 6 to the aluminum foil 1 by extrusion in severalsteps. The extrusion is carried out in such a way that the polyamidewill not substantially crystallize. The coating thus formed is attachedto an expanded or cellular polyurethane layer 3 while it is beingformed. The forming reaction of polyurethane is exothermic, whereby thecoating is also heated. During the manufacturing process, the polyamidelayer 2 is heated to the crystallization temperature of polyamide (e.g.120 to 140° C., such as 125 to 135° C., typically about 130° C.),whereupon the polyamide crystallizes. The necessary crystallization timemay be, for example, 1 to 5 minutes. In the selection of the polyamide,its extrusion properties are also taken into account.

Using the coextrusion technique can reduce the number of manufacturingphases.

The polyamide in the polyamide layer 2 is flexible and glutinous orviscous when uncrystallized. Thus, the coating is easily runnable, andit withstands the process well without tearing. When it crystallizes,the polyamide layer becomes stronger and stiffer, thereby producing aninsulation material that is sufficiently strong and stiff in use. Thecrystallized polyamide also increases bursting strength.

In the embodiment shown in FIG. 2, there is an aluminum layer 1.1, ontop of which a polyamide-6 layer 2.1 has been applied. The coating thusformed has been attached to the polyurethane layer 3.1 in such a waythat the aluminum layer 1.1 remains there-between.

In order to enhance the adhesion of the aluminum layer 1.1 and thepolyamide layer 2.1, an adhesion layer 4.1 is provided between them. Theadhesion layer 4.1 may contain a pigment more particularly a whitepigment. Correspondingly, in order to increase the adhesion between thealuminum layer 1.1 and the cellular polyurethane layer 3, a lacquerlayer 7 (e.g. about 2 μm) is provided between them.

The insulation material according to FIG. 2 can be manufacturedsimilarly to the material according to FIG. 1 described above. Thecoating can be formed by coextrusion in two steps, more particularly byattaching first a polyamide layer 2.1 and an adhesion layer 4.1 to eachother, and then these layers to an aluminum layer 1.1 and an adhesionlayer 7.

In the embodiment shown in FIG. 3, there is a layer of fibre wool 8(e.g. mineral wool, about 50 mm), on top of it a layer of a non-wovenmat 9 (e.g. glass fibre mat, about 50 g/m²), a plastic layer 10 (e.g.polyethylene, about 40 μm²), an adhesion layer 5.1 (e.g. about 2 μm), apolyamide layer 2.2 (e.g. about 30 μM), an adhesion layer 4.2 (e.g.about 2 μm), a layer of aluminum foil 1.2 (e.g. about 50 μm), and alacquer layer 6.1 (e.g. about 3 μm). During the manufacture, heat isintroduced from above through the entire layer. Melting occurs at atemperature of, for example, 140 to 160° C., typically at approximately150° C.

Furthermore, FIG. 4 presents a product corresponding to FIG. 2, in whichthe insulation is a layer of polystyrene foam (EPS) 3.2. On top of it,there is a layer of hot seal lacquer 7.1 (e.g. about 2 μm), a layer ofaluminum foil 1.3, an adhesion layer 4.3 (e.g. about 2 μm), and apolyamide layer (e.g. about 30 μm). In the manufacture, the heat isapplied from above. The polystyrene foam 3.2 melts and adheres to thehot seal lacquer 7.1.

The insulation materials according to the invention can be manufacturedto meet fire regulation norms.

1. A method for manufacturing a porous insulation material comprising aporous insulation layer, a metal layer and a polyamide layer, and twoadhesive layers, the method comprising: extruding one of the adhesivelayers onto the metal layer; extruding a glutinous not substantiallycrystalline polyamide onto the extruded adhesive on the metal layer toform a metal/glutinous polyamide layer; forming the porous insulationlayer; adhesively affixing the glutinous polyamide/metal layer with theextruded adhesive to the insulation layer while the porous insulationlayer is being formed and the polyamide is glutinous and notsubstantially crystalline to form a metal/glutinous polyamide/insulationlayer; and heating the glutinous polyamide in the metal/glutinouspolyamide layer and crystallizing the polyamide in the metal/glutinouspolyamide/insulation layer and form the insulation material.
 2. Themethod of claim 1 wherein the metal layer is an aluminum layer.
 3. Themethod of claim 1 wherein the polyamide is selected from the groupconsisting of polyamide-66, polyamide-6 and mixtures thereof.
 4. Themethod of claim 1 wherein the glutinous polyamide is heated to about 100to about 160° C.
 5. The method of claim 1 wherein the insulation layerincludes an expanded plastic.
 6. The method of claim 5 wherein theinsulation layer expanded polystyrene.
 7. The method of claim 1 whereinduring the formation of the insulation layer, an amount of heat isgenerated that is effective for crystallizing the glutinous polyamide inthe metal/glutinous polyamide/insulation layers.
 8. The method of claim1 wherein the extruded adhesive layer and the glutinous polyamide arecoextruded together onto the metal layer.